A surgically formed gastrostomy is a preferred method for administering enteral nutrition when oral alimentation is not possible. However the placement and formation of a gastrostomy requires a laparotomy performed under general anesthesia. Such requirements are unacceptable, particularly in patients who present a high general anesthetic risk. Hence a percutaneous endoscopic technique was developed which may be performed under local anesthesia and requires no laparotomy. This technique is disclosed of example in Gauderer & Ponsky, "A Simplified Technique For Constructing A Tube Feeding Gastrostomy", Surgery, Gynecology & Obstetrics, vol. 152, 1/81, pp. 82-85, the teachings of which are incorporated herein by reference. In addition, a percutaneous endoscopic formation of a gastrostomy may be performed by a gastroenterologist rather than a surgeon.
Generally, in forming a gastrostomy using a percutaneous endoscopic technique, an illuminating fiberoptic endoscope is inserted into a patient's mouth and advanced into the stomach. The stomach is then inflated with room air and the positioning of the endoscope may be externally visualized by the illuminated tip of the endoscope. The abdominal and gastric walls are then pierced at the positioning of the endoscope and the gastroscope thereby formed.
In order to intubate the gastrostomy, one end of a suture thread is passed externally through the gastrostomy. The one end of the suture is snared by the endoscope and drawn upward through the stomach, esophagus and out of the mouth of the patient. The suture is then tied to the end of a specially prepared catheter. The catheter is typically a 12 to 20 Fr. Pezzer or mushroom-type catheter in which a tapered cannula has been secured to one end of the catheter. The tip of the cannula carries a length of suture to permit the catheter to be tied to the one end of the suture extending from the patient's mouth. A previously removed connecting end of the Pezzer catheter is placed over the catheter and positioned slightly above the mushroom tip of the catheter to function as one perpendicular bumper for retaining the intubated catheter within the gastrostomy.
The catheter is then intubated by pulling it in a retrograde manner through the mouth, esophagus and into the stomach until the perpendicular bumper above the mushroom tip abuts against inner surfaces of the gastrostomy and the gastric wall. A second perpendicular bumper is placed over the catheter and secured to the abdominal wall to form an anchoring structure of the type disclosed in FIG. 6 of the Gauderer & Ponsky reference cited above.
There are many problems with the prior art percutaneous endoscopic catheters. The first perpendicular bumper placed above the mushroom retention tip includes several edges which result in an uncomfortable and difficult intubation of the catheter. Preferably, the retention tip should be more pliable and have a contoured, edge-free outer configuration to promote a relatively comfortable intubation of the catheter.
In addition, the prior art perpendicular bumpers which abut against the gastric and abdominal walls exert concentrated, abrasive contact pressure on specific tissue areas. Such specific contact has been found to create necrosis of the affected tissue. Hence, a need arose for an anchoring system for the retention tip of the intubated catheter which would evenly diffuse retention pressure on the surrounding affected tissue to avoid tissue necrosis.
Further, the inner perpendicular anchoring bumper in some cases would pull free and in most cases was difficult to remove upon conclusion of enteral feeding therapy. Removal is now achieved either by physically pulling the retention tip through the gastrostomy or allowing the tip to pass freely through the gastroenteral tract to become excreted. Either alternative is uncomfortable for the patient and subject to complications. Hence, a need arose for an anchoring and retention tip which could be easily and comfortably removed at the conclusion of enteral feeding therapy through the gastrostomy.
Prior to the development of the present invention, a need existed for a catheter specially designed for intubating a gastrostomy or an other ostomy formed by a percutaneous endoscopic technique having (1) an enlarged retention member which is pliable and smoothly contoured for a more comfortable intubation, (2) anchor means which more evenly distributes contact with to surrounding tissues thereby avoiding tissue necrosis, (3) anchor means which remain abutted against tissue surrounding the ostomy without pulling free and, (4) an anchor means and retention member which may be compressed or collapsed to facilitate removal of the tube externally through the gastrostomy itself upon completion of enteral feeding therapy. Preferably, unlike the prior art retention tip and bumpers, a most efficient catheter design would combine the anchor means and retention member into a single structure.